It took a while but I found an NOS GEC/MWT U52 5U4G. After extended listening I find the Sophia Aqua 274B to be a little bright in my Modwright PS 9.0 power supply, and soundstage depth to be a little lacking. The U52 is more midrange centered, has superior tone and timber, and expands the soundstage particularly front to back, compared with the Aqua 274B. It is the best rectifier I've ever heard in the PS 9.0. 2nd best among the rectifiers I tried in the PS 9.0 was a 1940's military Tung Sol 5U4G black plate.
Modwright PS 9.0 and 9.9 Power Supply Rectifiier Tubes
After extensive listening to more than a dozen different rectifiers, I concluded that my Phillips
5R4GYS, 1949 RCA 5U4G, and 60's Mullard GZ32 5V4 were superior in the PS
9.0 and 9.9 to any 5AR4/GZ34 I have tried including NOS Mullards and the Phillips
metal base 5AR4. The RCA 5U4G and Mullard 5V4 are pretty close in sound
quality, and both are more articulate and natural sounding than the
Phillips 5R4GYS. I also picked up an NOS 1944 Tung Sol 5U4G (not the
5U4GB) which by a small margin (lower noise floor) was the best
rectifier tube I had heard in the Modwright PS 9.0 and 9.9 until the new Sophia
Electric blue 274B arrived in today's mail. This special 274B is
designed to be a direct replacement for the 5U4G (and substitutes). I started listening
to it in the PS 9.0 and right out of the box it produced the most
natural piano tone I have ever gotten from my system. With about 30 hours on it I am comfortable in saying that it is the best sounding rectifier that I have ever heard in the PS 9.0 and 9.9.
Jeff Day has reviewed this tube for Positive Feedback and on his "Jeff's Place" blog for anyone who is interested.
Jeff Day has reviewed this tube for Positive Feedback and on his "Jeff's Place" blog for anyone who is interested.
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- 12 posts total
- 12 posts total